I bought a glowshift air-fuel/volt combo gauge -
there are 4 wires
1 ground
1 switched 12v ignition(hooked up to 12v accessory wire)
1 constant 12v
and 1 to o2 sensor sigal output

i have a 6th gen civic 96 dx
i have looked at other form but i cant figure out what wire is the
signal one..
i have 1 green 1 white and 2 black-these are all coming from the o2 sensor

im not sure what wire it is,
if possible what is the color wire that connect to the computer unit that i can tap into.

also the gauge after about to minute starts flashing and reading 20v with the engine not running-this is with all but the grey wire hooked up

Thanks for the help

 

Look at the wires on the harness side of the sensor plug. I think the output wire is white, which should mate to either the white or green wire on the sensor. Reaize that the stock narrowband sensor doesn't produce much useful information for one of those gauges.

The voltage sensing wire should have its own direct (with a fuse) connection to the battery for most accurate results.

 

This. It is just going to be a pretty light show in your car.